Date of Award

Fall 12-2025

Document Type

Thesis

Degree Name

Master of Science (MS)

Department/Program

Forensic Science

Language

English

First Advisor or Mentor

Yi He

Second Reader

Shu-Yuan Cheng

Third Advisor

Marin Kurti

Abstract

Electronic cigarettes, or e-cigarettes, have become popular as electronic nicotine delivery systems (ENDS) since the early 2000s. Flavoring compounds are commonly added to e-liquids to enhance the product appeal. Although some flavorants were approved for food consumption, the safety of inhaling aerosol from flavored ENDS products remains unknown. In this work, a gas chromatography-mass spectrometry (GC-MS) method was developed for determination of chemical components present in various e-liquids and e-liquid aerosol samples. Compounds were identified through mass spectrum comparison with the NIST standard library and then followed by chemical confirmation for representative compounds. Propylene glycol (PG), nicotine, and vegetable glycerin (VG), which are the major components of most ENDS, were identified and quantified. Although the PG/VG ratios differed among different brands and sample types, this ratio was consistent within the JUUL brand as 30/70. Calibration curves were built for chemically confirmed compounds. Correlation coefficients of R2>0.99 were obtained for all analyses. Nicotine concentrations differed at a maximum of ±0.93% and were mostly agreeable with the manufacturer labels. Out of 40 identified compounds, 37 compounds were flavoring compounds. Wide differences in the concentrations of flavoring compounds found in e-cigarette products suggested that these compounds were added in amounts that were not closely monitored resulting from the lack of regulation. Between brands, the flavorants used for similarly flavored e-cigarette products have little to significant variation. Same base flavoring compounds were typically used within the same brand and varying additional flavorants were added depending on the specific flavor of the e-cigarette product.

Available for download on Saturday, December 18, 2027

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